Key Takeaways
- • Seth Platt, Siegel's representative on Two Sigma's two-person management committee, is preparing to leave the $85bn hedge fund, according to Bloomberg, and has asked that a replacement be found before he departs.
- • Platt's exit will require David Siegel to select a third representative in approximately two years, adding to the governance strain between co-founders Siegel and John Overdeck.
- • The departure follows months of disagreement over whether Platt should also serve as co-chief executive alongside Carter Lyons, who was appointed by Overdeck.
- • Two Sigma's Absolute Return Enhanced Fund gained 16% through September, and the firm said 2026 was on track to be one of its strongest years.
- • Platt will remain chief investment officer and chief operating officer of Siegel's family office after leaving the hedge fund.
Summary
Two Sigma Investments is facing another senior leadership departure as Seth Platt prepares to leave the $85bn hedge fund amid a prolonged governance dispute between co-founders David Siegel and John Overdeck, according to a Bloomberg report. Platt served as Siegel's representative on the firm's two-person management committee. He has requested that a replacement be found and will depart once a successor is appointed. His exit will require Siegel to select a third representative in approximately two years.
The departure follows months of disagreement over whether Platt should also serve as co-chief executive alongside Carter Lyons, who was appointed by Overdeck. Siegel and Overdeck, who founded Two Sigma in 2001, stepped down as co-chief executives in 2024 after years of tensions that the firm had previously disclosed as a material risk in a 2023 regulatory filing.
The management committee has seen considerable turnover. Siegel initially appointed former Lazard general counsel Scott Hoffman as his representative, while Overdeck selected Lyons. Overdeck later returned to the management committee, and Hoffman resigned in March 2026, citing ongoing governance challenges. Platt was appointed as his replacement.
Despite the leadership instability, Two Sigma has reported strong investment performance, with its Absolute Return Enhanced Fund gaining 16% through September. The firm said 2026 was on track to be one of its strongest years. Platt will continue as chief investment officer and chief operating officer of Siegel's family office. A spokesperson for the family office said Siegel has no plans to return to day-to-day management of the hedge fund, and a search is underway for Platt's successor.
The departure follows months of disagreement over whether Platt should also serve as co-chief executive alongside Carter Lyons, who was appointed by Overdeck. Siegel and Overdeck, who founded Two Sigma in 2001, stepped down as co-chief executives in 2024 after years of tensions that the firm had previously disclosed as a material risk in a 2023 regulatory filing.
The management committee has seen considerable turnover. Siegel initially appointed former Lazard general counsel Scott Hoffman as his representative, while Overdeck selected Lyons. Overdeck later returned to the management committee, and Hoffman resigned in March 2026, citing ongoing governance challenges. Platt was appointed as his replacement.
Despite the leadership instability, Two Sigma has reported strong investment performance, with its Absolute Return Enhanced Fund gaining 16% through September. The firm said 2026 was on track to be one of its strongest years. Platt will continue as chief investment officer and chief operating officer of Siegel's family office. A spokesperson for the family office said Siegel has no plans to return to day-to-day management of the hedge fund, and a search is underway for Platt's successor.
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